1. Field of the Invention
Examples of the subject matter disclosed herein generally relate to apparatus, methods and systems for separating gases from liquids in a down-hole hydrocarbon production environment.
2. Discussion of Background
The present invention relates to developments in separating gases from hydrocarbon-bearing liquids that exist in oil reservoirs, with particular emphasis on extracting or separating the gases prior to the oil-bearing fluid reaching pumps. It is known that gases adversely affect pump efficiency and removal of gases prior to entry of the fluid into the pump is desired.
U.S. Pat. No. 1,973,650 to O'Brien discloses a GAS AND LIQUID SEPARATOR. O'Brien '650 discloses that separation of the gas from the oil is effected at the time the oil reverses its direction of movement. The separated gas continues upwardly through the passageway and flows outwardly through openings into the well casing through which it can be separately withdrawn exteriorly of the working barrel. The oil freed from gas flows downwardly through the chamber and is drawn into the tube through openings where it again reverses its direction of travel, flowing upwardly through the tube and working barrel. Any loose sand which is carried by the stream of oil in its circuitous passage through the separator, drops downwardly by gravity and due to its own inertia on lateral deflection of the stream from the chamber into the tube. However, O'Brien '650 fails to disclose a series of individual gas separation cylinders, a collection of downward conveying delivery tubes, burp tubes to convey upward separated gas. O'Brien '650 fails to disclose burp tubes to moderate the fluid levels in each separation cylinder and fails to provide structural components to amplify the effect of surface tension breakout.
U.S. Pat. No. 2,429,043 to Barnhart discloses a bottom hole gas anchor, the gas anchor having a housing of a maximum diameter size which can be safely deposited in the well so as to provide a maximum size expansion chamber which will permit the maximum reduction in the velocity of flow of the gas, liquids and solids from the formation to the pump. Barnhart '043 discloses that another object of the invention is to reduce the velocity of flow progressively step by step to a minimum so as to encourage the separation of the gases, liquids and solids. This separation is accomplished by providing a plurality of passages for the flow of the material in the assembly whereby the flow thru any other passage or passages after the first passage obtains a further reduction in the velocity of flow compared with the velocity in the first passage. Barnhart '043 is directed to a bottom hole gas anchor and not a production string gas separator. Barnhart '043 fails to disclose two sets of overlapping tubes. A first series of elongated tubes which downwardly overlap with a second series of upwardly overlapping elongated tubes to effect gas-liquid separation. Barnhart '043 fails to disclose use of polytetrafluoroethylene (PTFE) surfaced tubing, fails to disclose use of burp tubes, fails to disclose means for cascading a plurality of gas separator units/cylinders with associated gasketing system, fails to use a gravel or sand medium to further effect gas-liquid separation.
U.S. Pat. No. 4,241,788 to Brennan discloses a MULTIPLE CUP DOWNWELL GAS SEPARATOR. Each retention cup has a retention chamber which provides a fluid retaining capacity sufficient to momentarily retain well fluid flowing from the well so as to permit gas to escape from the fluid so retained and returned to the well. The difference in specific gravity between gassy well fluid and well fluid with gas removed creases circulation of well fluid through the retention cups and into the reservoir chamber, with each retention cup catching down falling well fluid that has been partially freed of entrained gas. Second stage separation of gas from well fluid is achieved by providing at least one opening or passageway from the reservoir chamber adapted to provide a gas exit between the well and the reservoir chamber.
U.S. Pat. No. 4,366,861 to Milam discloses a DOWNHOLE GAS SEPARATOR. Milam '861 discloses a gas separator being secured to the lower end of the pump and generally comprises inner and outer concentrically arranged tubes extending downwardly within the well tubing. The well fluid contained in the well bore is drawn into the well casing and travels through a long, torturous upward and downward path through the well tubing and gas separator and to the surface of the well bore.
Milam '861 discloses attaching a separator directly to a rod pump, teaching away from attaching the separator to the production string. Further, being connected to the rod pump would limit the diameter of the separator to the inside diameter of the production string.
U.S. Pat. No. 4,676,308 to Chow et al. discloses a DOWN-HOLE GAS ANCHOR DEVICE. The device comprises a means to divert hydrocarbon production fluid from within a tubing string into the annulus of the well. This diversion turbulently mixes the fluid and releases free gas from the liquid. Thereafter, the liquid migrates downward while the free gas migrates upward to a gas collection apparatus.
Chow et al. '308 teaches away in that Chow '308 turbulently diverts the flow of production fluid and does not provide means for non-turbulently diverting the flow of production fluid to separate the gas from the liquids.
U.S. Pat. No. 5,389,128 to Lopes discloses a MULTIPLE, SELF-ADJUSTING DOWNHOLE GAS SEPARATOR. The multiple, self-adjusting downhole gas separator includes an external decanting pipe having perforations about the periphery thereof, and a concentric inner suction pipe equipped with inverted L-shaped suction pipe by-passes extending outwardly and downwardly from the periphery of the inner suction pipe. A plurality of respective retention cups are resiliently supported on the inner suction pipe by elastic elements.
U.S. Pat. No. 6,179,054 B1 to Stewart discloses a DOWN HOLE GAS SEPARATOR. A slotted gas separator for a down hole pump has an internal baffle that is angled to push the oil down into the chamber and the gas up to be released. The baffle has a roughened surface area with small, grainy protrusions that result in a jagged, coarse surface to agitate the liquid-gas mixture and separate out any gas. The large surface area of the baffle insures maximum contact to separate the oil and gas. The gas is released through slots on the top of the casing.
U.S. Pat. No. 7,377,314 B2 to Gonzalez discloses a DOWNHOLE GAS SEPARATOR. The downhole gas separator includes an external tube having a closed bottom and an open top; and an internal tube positioned eccentrically within the external tube and having an open bottom and a top adapted for connection to a production tube. The internal tube can alternatively be connected to a pump intake. The separator is positioned eccentrically within a casing, and provides for separation of gas from produced fluids before the fluids enter the production tube and/or pump.
US Patent Publication 2013/0032341 A1 to Raglin discloses a DOWN-HOLE GAS SEPARATOR. A baffle assembly in the gas separator is comprised of a series of baffles, each baffle extending between an inner wall of the central tube and an outer wall of the suction tube for a portion of the available space between the inner wall of the central tube and the outer wall of the suction tube, each baffle offset from the other baffles in the baffle assembly, wherein the baffle assembly is operable to continually redirect the fluid and gas as it travels through the central tube.
Brennan '788 & Milam '861 & Chow et al. '308 fail to disclose a cascaded separator having it separator components contained within a constant outside diameter to prevent binding or sanding up of the separator when deployed downhole. The upwardly open retention cups are exposed externally and subject to sanding up.
Brennan '788 & Milam '861 & Chow et al. '308 & Lopes '128 & Stewart '054 fail to disclose two sets of overlapping tubes. A first series of elongated tubes which downwardly overlap with a second series of upwardly overlapping elongated tubes to effect gas-liquid separation.
Brennan '788 & Milam '861 & Chow et al. '308 fail to disclose use of polytetrafluoroethylene (PTFE) tubing. Lopes '128 & Stewart '054 fail to disclose use of polytetrafluoroethylene (PTFE)-surfaced tubing.
Brennan '788 & Milam '861 & Chow et al. '308 & Lopes '128 & Stewart '054 fail to disclose use of burp tubes.
Brennan '788 & Milam '861 & Chow et al. '308 & Lopes '128 & Stewart '054 fail to use a gravel or sand medium to further effect gas-liquid separation.
Milam '861 & Chow et al. '308 & Lopes '128 & Stewart '054 fail to disclose means for cascading a plurality of gas separator units/cylinders with associated gasketing system.
The inventor indicates that old experiments included “cups” around a production pipe, open upward, therefore creating an upwardly open annular region around the pipe. Gaseous fluids would enter into the upwardly open “cup”, providing time for gas to evolve before entering into the production pipe at the bottom of the “cup”. This failed for various reasons, including the problem that the cup would fill with clay or sand or other debris and plug up. They would “sand up”. The inventor believes that these problems have caused practitioners to reject using cups, and the art to teach away from use of cups. This has bothered the inventor for many years. The inventor now realizes that perhaps these problems may have been created by these experimental cups being greater diameter than the diameter of the pipe. Upon this realization, the inventor has sought ways to solve the plugging problem, resulting in the creation of an internal cup without a protruding diameter that will not “sand up.”